Composition for coating frozen-food carton board



COWQSKTION FGR CQATKNG FROZEN-FOUD CARTQN BQARD t William H. J. Nussle, in, Eroornall, Pa. assiguor to The 7 Atlantic Refining Companwl hiladeiphia, Pa, 2 corporation of Pennsylvania No Drawing. Filed Apr. 4, 1962.,Ser. No. 134,022

5 Claims. (Cl. 260-=28.5)

This invention relates to coating compositions for frozen-food carton board and, more particularly, to pctroleum hydrocarbon wax-containing coating compositions suitable for use at low temperatures.

A composition suitable for coating frozen-food carton board and ice cream carton board is required to have certain essential properties. It must adhere to the printed United States Patent 0 side and to'the unprinted side of the carton board Without cracking or crazing at tempera-tures down to -60 F. it must have a high blocking temperature so that the coated sheets (blanks) will not adhere to each other in storage and allow smooth feed from stacks, a single sheet at a time, into high speed packaging equipment The coating also should have a high gloss and good gloss stability so that the printing and package attractiveness will be enhanced for customer appeal.

The composition of the instant invention has all of these essential properties and, in addition, it is economical and easily applied to carton board. t

It is an object of this invention to provide a coating composition for frozen-food carton board.

It is another object of this invention to provide a petroleum hydrocarbon wax-containing coating composition for frozen-food carton board which may be used at low temperatures, which has a high blocking temperature, and which has a high gloss with good gloss stability.

Other objects of the invention will be apparent from the following detailed description of the invention and the claims. I Y

f The third-wax fraction is a r'efinedsenri-microcrystah line Wax produced from solvent refined lubricating oil distillate of 60-80 S.U.S. viscosity by solvent dewaxing and solvent deoiling using methyl ethyl ketone as the primary dewaxing, and deoilingsolvent. The wax is finished by conventional'clay filtration. The wax has a melting point ranging from 153 F. to 166 F. and is used in an amount ranging from 10 weight percent to 20 weight percent based on the total weight of the composition. Preferably, the amount employed ranges from 12 weight percent to 18 weight percent. g

The polyethylene component found to a mixture ofethylene polymers ranging in molecular weight from about 2,000 to 10,000 with the major amount "being in the molecular Weights in the middle of the range and the average molecular weight being about 6,000. A

polyethylene known by the trade name Epolene with a Ring and Ball softening point ranging from 105 C. to 111 C., viscosity at 125 C., Brookfield, rangingfrom 900 to 1500 centipoises, and a density at 77 F. of about 0.906 is comprised of a mixture of ethylene polymers in In-accordance with this invention, a combination. of

petroleum hydrocarbon waxes, synthetic resins, synthetic polymers and specific fatty acid amides has been found which meets the rigid requirements of a coating composition'for frozen-food carton board.

-The wax portion of the composition is made up of three refined petroleum hydrocarbon waxes. The total quantity of these waxes ranges from 62 weight percent to 80 weight percent based on the total weight of the composition, and preferably from 68 weight percent to 80 weight percent.

The lowest meltingwax employed is a refined petroleum parafiin hydrocarbon wax melting from 140 F. to 145 F.

, in an amount ranging from 12 weight percent to 16 weight percent based on the total weight of the composition and preferably from 13 weight percent to 15 Weight percent. This wax is produced byconventional solvent extraction of Waxy distillate oils using, for example, methyl ethyl ments to give coatings with inferior gloss and coefiicients etone as the solvent with conventional finishing using acid treating,'if desired, followed by clay filtration. g,

The second wax component-is a refined petroleum paraffin hydrocarbon wax melting from 150 to .155 F.

It may range in an amount from 40 weightpercent to 50 weight percent based on the total weight of the cornposition, with the preferred rangebeing from 43 Weight percent to 47 Weight percent. This wax is a fraction having a higher melting point than the first wax component, but it-may be produced in the same manner.

this molecular weight range and having the described desired distribution of molecular weights. This polyethylene component has been found to besuitable in amounts ranging from 14 weight percent to 20 weight percent based on the total weight of the composition.

The terpe-ne resin component is a hydrocarbon thermo-.

Patented Dec. 29, 1964 be suitable is plastic terpene resin produced by catalytically polymerizing pinenes, predominantly beta-pinene, suchas the ter pene resin known by the trade name Piccolyte 8-100. This resin has a melting point of about 100 C. (tolerance 13 C.) by the Ring and Ball softening point method. This resin is very pale amber in color, acid number less than 4 (approximately zero), sapom'fication number'less than 4 (approximately zero) with a specific gravity of :about 1.0. It is employed in amounts ranging from 2.5

weight percent to 6.0 weight percent based on the weight of the composition.

Y The amide ingredient of the composition is employed in the least amount, but this component has been found to be extremely critical with respect to gloss and reduction of coefiicientof friction of the coating. It has been found that from 0.5 weight percent to 3.0- weight percent based on'the total weight of the composition of either the amide of oleic acid or the amide of stearic acid imparts the neces friction so that the coated carton blanks will slip easily and smoothly over each other. The amides of the higher molecular weight fatty acids and the lower molecular weight fatty acids have been found by repeated experiof friction, i.e., poor slip. Likewise, the more highly unsaturated C fatty acid amides give inferior coatings.

The composition of this invention is prepared conveniently by adding the desired quantities of wax'to a vesselduring the coating operation.

"When applied to carton board in a thin film and water quenched (about 40 F.) this composition gives a coating sary gloss to the coating and reduces the coefficient of v having a very high gloss, i.e. 70 percent to 80 percent refiectance as measured by the 20 Specular Gloss method ASTM (D-1834-61T). It adheres to the carton board without cracking or crazing after the coated board has been held at 60 F.for 24 hours. The composition has a blocking temperature of 125 F. or more as measured by the gradient method ASTM (D-1465-5'7T).

The examples which follow are provided for illustrative purposes only and are not to be construed as limiting the invention thereto. 3

Example I A composition was prepared which contained the following ingredients, the amounts being in weight percent based on the weight of the total composition:

Petroleum parafiin wax, 143 F., MP 14 Petroleum parafiin wax, 151 F., M.P 45 Petroleum semi-microcrystalline wax, 153 F., MP... 15

Polyethylene, Epolene,- polymers ranging in molecular weight from 2,000 to 10,000 Terpene resin, Piccolyte S-l00, 100 C., M. P. 5 Oleamide (amide of oleic acid) 1 This composition had a blocking temperature above 125 F. by the gradient method and was used to coat a 12-point white sulfite paper board sized on one side. The coated board had a high gloss, about 80 percent reflectance by the 20 Specular Gloss method. The coating adhered to the board without cracking or crazing after the coated board had been held 24 hours in a cold room at -60 F. A stack of the coated sheets was held at 73 F. for 24 .hours under a static load of 0.125 pound per square inch on the sheets. The sheets did not adhere to each other at the end of the test. The sheets were found to have a very low coefficient of friction, i.e. they slipped easily over each other and were found suitable for use in commercial high-speed packaging machines. In addition, the coating .was found to have extremely good scuff resistance.

Example II A composition was prepared which contained the following ingredients, the amounts being in weight percent based on the weight of the total composition:

Petroleum parafiin wax, 143 F., M.P. (same as Example I) 24 Petroleum paraffin wax, 151 F., M.P. (same as Example I) Petroleum semi-microcrystalline wax, 153 F., M.P.

(same as Example I) 15 Polyethylene (same as Example I) 20 Terpene resin (same as Example I) 5 Oleamide (same as Example I) 1 This composition failed to adhere to the paper board after the paper board which was coated with it had been subjectedto the cold room test for 24 hours at -60 F. This composition ditferered from that of Example I only in the proportions of the parafiin waxes.

Example III A composition was prepared which contained the following ingredients, the amounts being in weight percent based on the weight of the total composition:

Petroleum paraffin wax, 143 F., M.P. (same as Example I) Petroleum paraffin wax, 151 F., M.P. (same as Example I) Petroleum microcrystalline wax, 173 F., M.P. 15 Polyethylene (same as Example I) 20 Terpene resin (same as Example I) 10 Oleamide (same as Example I) 1 This composition failed the blocking test and the coated sheets stuck together when stacked. This composition also failed to adhere to the paper board after the paper board which was coated with it had been held at 60 F. for

consisting essentially of the following ingredients in weight percent based on the weight of the total composition:

Panafiin wax, M.P. 140 F. to 145 F. 12-16 Paraffin wax, M.P. 150 F. to 155 F 40-50 Semi-microcrystalline wax, M.P. 153 F. to

166 F. 10-20 Polyethylenes, molecular weight range, 2,000

to 10,000 14-20 Terpene resin, M.P. about 100 C 2.5-6.0 C18 ...L. 'O.53.0

wherein the total quantity of wax does not exceed weight percent, the terpene resin is polymerized pinenes, the major proportion of said pinenes comprising beta pinene, and the C amide is selected from the group consisting or" oleamide and steairamide.

2. A composition for coating frozen-food carton board consisting essentially of the following ingredients in weight percent based on the wieght of the total composition:

'Parafiin wax, M.P. 140 F. to 145 F 13-15 Paratlin wax, M.P. 150 F. to 155 F. 43-47 Semi-microcrystalline wax, M.P. 153 F. to

166 F. 12-18 Polyethylenes, molecular weight range, 2,000

to 10,000 14-20 Terpene resin, M.P. about C. 2.5-6.0 C amide 0.5-3.0

wherein the total quantity of wax does not exceed 80 weight percent, the terpene resin is polymerized pinenes,

the major proportion of saidv pinenes comprising beta pinene, and the C amide is selected from the group consisting of oleamide and stearamide.

3. A composition for coating frozen-food carton board consisting essentially of the follwing ingredients in weight percent based on the weight of the totalcomposition:

Paratfin wax, MP. F. to F 12-16 Paraflin w-ax, M.P. F. to F. I 40-50 Semi-microcrystalline wax, M.P. 153 F. to

166 F. Polye-thylenes, molecular weight range 2,000

to 10,000 14-20 Terpene resin, M.P. about 100 C 2.5-6.0 Oleamide 0.5-3.0

wherein the total quantity of wax does not exceed 80 weight percent and the terpene resin is polymerized pinenes, the major proportion of said pinenes comprising beta pinene.

4. A composition for coating frozen-food carton board consisting essentially of the following ingredients in weight percent based on the weight of the total composition:

Parafiin wax, M.P. 140 F. to 145 F. 12-16 P-aratfin wax, M.P. 150 F. to 155 F 40-50 Semi-microcrystalline wax, M.P. 153 F. to

166 F. 10-20 Polyethylenes, molecular weight range 2,000

to 10,000 14-20 Terpene resin, M.P. about 100 C. 2.5-6.0 Stearamide 0.5-3.0

wherein the total quantity of wax does not exceed 80 weight percent and the terpene resin is polymerized pi- 7 3,163,617 5 6 nenes, the major proportion of said pinenes comprising wherein the terpene resin is polymerized pinenes, the major beta pinene. proportion of said pinene comprioing beta pinene.

5. A composition for coating frozen-food carton board consisting essentially of the following ingredients in Weight percent based on the Weight of the total composition: 5

References Cited by the Examiner v UNITED STATES PATENTS 2,453,644 11/48 Steinkraus 260-28.5 A

Pamaffin Wax, M.P. about 143 F. 14 2,814,610 11/57 Braidwood et a1. 26093.3 Paraflin Wax, M.P. about 151 F. 45 3,061,493 10/62 Anderson 26028.5 A Semi-microcrystalline wex, M.P. about 153 F. 15 OTHER REFERENCES Polyethylenes nangmg 1n molecular weight from 10 2 000 to 10 000 29 Pages 37, 1948, Piocolyte the Versatile Resin, Penn- Tergene m. 55;;5553;333:333? 5 sylvam'a Industrial chm imp-114mm, Oleamide 1 MORRIS LIEBMAN, Primary Examiner. 

1. A COMPOSITON FOR COATING FROZEN-FOOD CARTON BOARD CONSISTING ESSENTIALLY OF THE FOLLOWING INGREDIENTS IN WEIGHT PERCENT BASED ON THE WEIGHT OF THE TOTAL COMPOSITION: 